please show work for A,B,C

Perpetual Inventory Using Weighted Average Beginning inventory, purchases, and sales for H76 are as follows: July 1 Inventory 300 units at $120 12 Sale 210 units 23 Purchase 360 units at $135 26 Sale 330 units a. Assuming a perpetual inventory system and using the weighted average method, determine the weighted average unit cost after the July 23 purchase. per unit b. Assuming a perpetual inventory system and using the weighted average method, determine the cost of the merchandise sold on July 26. $